A. Polybutadiene-polyethylene oxide (PBD-PEO) diblock co-oligomers
U.S. Pat. No. 4,279,798 to Aggerwal et al., discloses PBD-PEO block copolymers of low molecular weight, e.g. 4000 M.W. The diblock is formed by preparing a hydroxy terminated polybutadiene prepolymer using an organo-lithium initiator, with subsequent addition of ethylene oxide using a double metal cyanide catalyst. These PBD-PEO diblocks are disclosed to be useful as dispersants for crude oil/alcohol mixtures. See also U.S. Pat. No. 3,978,160 to Seiler et al, issued Aug. 31, 1976, which discloses low molecular weight PBD-PEO diblocks (e.g. 3600 M.W.) suitable as anti-static agents, emulsifiers, surfactants and finishing agents for paper and textiles.
B. Aqueous polymer dispersions prepared using amphiphilic diblock copolymers
U.S. Pat. No. 4,385,164 to Sinclair et al., issued May 24, 1983, discloses aqueous dispersion polymerization of an unsaturated monomer such as butadiene in the presence of a block copolymer dispersion stabilizer. The stabilizer comprises 50-97% of a hydrophilic block (e.g. polyethylene oxide) and 3-50% of a hydrophobic block (e.g. polystyrene) having pendant functional groups (e.g. vinyl) capable of reacting with the monomer that is polymerized. The copolymer can have a weight average M.W. of from 1000 to 10.sup.6 with the hydrophilic block preferably having an M.W. of at least 4000, and the hydrophobic block preferably having an M.W. of at least 10,000. A free-radical initiator which is soluble in the monomer is used to catalyze the dispersion polymerization. The polymers formed can be used for coating and impregnating various substrates such as textiles, fabrics, paper, etc. Example 4 discloses the aqueous dispersion polymerization of butadiene to provide small polymeric spheres using a copolymer comprising 85% of a methoxy poly(ethylene oxide)-methylacrylate hydrophilic block and 15% of a t-butyl polystyrene hydrophobic block having pendant epoxy functional groups. This block copolymer had a number average M.W. of 10,460 and a weight average M.W. of 13,930.
C. Dispersion polymerization using amphiphilic diblock copolymers
U.S. Pat. No. 4,026,962 to Lambia et al., issued May 31, 1977, discloses a process for dispersion-polymerization of vinyl monomers (e.g., styrene) in water using a block copolymer of the A-B type wherein A represents a hydrophobic block and B represents a hydrophilic block. Suitable block copolymers include polystyrene-quaternized poly-(vinyl-2-pyridine), polystyrene-quaternized poly(vinyl-4-pyridine), and polyisoprene-quaternized poly(vinyl-4-pyridine). This process provides beads or balls of the desired polymer having very regular size distribution. See also U.S. Pat. No. 3,580,880 to Clarke, issued May 25, 1971, which discloses stable dispersions of polymer particles prepared by polymerizing an olefin type monomer in a liquid (e.g., water) in the presence of an amphiphatic stabilizer which associates with and stabilizes the dispersion of polymer particles formed.
D. Aqueous latexes formed by emulsion polymerization using a seed latex
U.S. Pat. No. 3,397,165 to Goodman et al., issued Aug. 13, 1968, discloses the preparation of butadiene polymer latexes useful as paper impregnants or for coating surfaces. These latexes are formed by providing a butadiene/styrene copolymer seed and then polymerizing butadiene and styrene monomers together with acrylic or methacrylic acid.
E. Aqueous latexes formed by emulsion polymerization using "shot growth" technique
U.S. Pat. No. 3,575,913 to Meier, issued Apr. 20, 1971, discloses a latex especially adapted for paper coating. This latex is formed by polymerizing a monomeric composition containing an unsaturated dicarboxylic acid (itacanoic acid), a vinyl aromatic (styrene), and a conjugated diene (butadiene). After at least 90% of the monomeric composition is polymerized, 1-5% of an acrylic acid monomer is added and then polymerization is continued.